Bergholt Stuttley Johnson, better known as Bloody Stupid Johnson, is a landscape gardener and inventor on the Discworld (a fictional world created by author Terry Pratchett), and is mentioned in a number of books. Though he has died before the timeline in which most of the books are set, his legacy lives on.

Although evidently able in certain fields, Johnson is notorious for his complete inability to produce anything according to specification or common sense. This fact never stopped him from trying, however. He is also known as Bloody Stupid "It Might Look A Bit Messy Now But Just You Come Back In Five Hundred Years' Time" Johnson and Bloody Stupid "Look, The Plans Were The Right Way Round When I Drew Them" Johnson.

Johnson was not incompetent, far from it; indeed in many ways he was a kind of genius. Pratchett suggests on numerous occasions that he possessed a kind of "inverse genius"; as far from incompetence as genius but in the opposite direction. Certainly no one else could produce an explosive mixture from nothing more than common sand and water, or create a triangle with three right angles.

The most obvious flaw in Johnson's abilities is his blind spot when it comes to marking units on his plans; examples include the Colossus of Morpork, which is currently kept in a matchbox in the Dwarf Bread Museum, and the ornamental cruet set commissioned by Mad Lord Snapcase — the saltshaker currently houses four families and they use the pepper mill to store grain. Those few of his works that are approximately the right scale typically either work in unexpected ways, or simply have a tendency to spontaneously detonate. His attempts at landscape gardening are equally surprising, including the enormous artificial hillock in front of Quirm Manor ("It'd drive me mad to have to look at a bunch of trees and mountains all day long, how about you?") and the hoho in the Ankh-Morpork Palace grounds, which is like a haha but fifty feet deep. His other works consist of a trout-pond in the grounds of the Patrician's palace that, due to the usual misunderstandings surrounding Johnson's work, is an ornamental trout pond that is only an inch wide, yet more than 100 feet in length. The sole trout occupant is very happy, provided he never has any desire to turn around.

While most of Johnson's designs are simply unusual, some of them seem to tap into strange forces, probably by mistake. The most obvious examples of this are the Mail Sorter and Empirical Crescent, but the tendency of his landscape work to spontaneously explode may be an indication of the same phenomenon. It has been suggested that he may have inadvertently achieved the exact opposite of constructing in cosmic harmony with the power of ley lines.

The fact that he continued to receive commissions after the defects in his abilities became apparent is considered to be the ultimate expression of the apparent thinking behind the Victorian follies, i.e. an indication that the person commissioning the work can afford to waste money like this. It became quite fashionable to have your house or garden 'Johnsoned'. This view of Johnson's abilities was not universal, however: it is believed that the town house of the Ramkin family — a rather pleasant old house with well-designed gardens — was never worked on by Johnson because he was shot in the leg by the then owner while walking up its drive one day. They do however have the "Johnson Exploding Pagoda."

Generally assumed to be dead in the time of most of the books, Johnson is never seen, but was certainly alive around the time of the main events of Night Watch: Mr Snapcase took up the Patricianship in the course of the events chronicled at that time, and he could only have commissioned the Ornamental Cruet Set from Johnson after becoming Patrician. This is also approximately when Johnson must have created the ill-fated mail sorter, as dates in Going Postal suggest that this occurred 30 years before the events chronicled there. Given the nature of the sorter, this may not be a problem.

Johnson's name and abilities are a parody of Capability Brown and also, perhaps, a typically conservative swipe at the experimental novelist B. S. Johnson. While some see a pun in the initials B.S.J. (the reverse of J.S.B., the initials for the famous real world composer Johann Sebastian Bach), Pratchett has stated (online and in The Discworld Companion) that this was not intentional.